I. Field of the Invention
This invention relates generally to electrosurgical instruments, and more particularly to an improved forceps whose jaws are especially designed to facilitate selective cutting, desiccation and sealing of tissue structures without the need for an instrument exchange.
II. Discussion of the Prior Art
The prior art is replete with electrosurgical forceps for use in open and laparoscopic procedures to cut through tissue structures, desiccate the tissue and any blood vessels to stem bleeding and for creating a fluid-tight seal between tissue structures along the margins of a cut. The Stern et al. U.S. Pat. No. 5,443,463 describes a coagulating forceps for use in open procedures in which the cooperating faces of its opposed jaws are generally planar and support a plurality of electrodes on one jaw and temperature sensing elements on the opposed jaw. Cutting of tissue is by way of a sharp blade that is actuated following electrocoagulation on opposed sides of the cut line.
The Fineburg U.S. Pat. No. 5,458,598 describes an endoscopic cutting and coagulating device, which, like the Stern '463 device has opposed jaw members whose opposed jaws are generally identical, each having a U-shape defining a central slot and with generally planar, albeit serrated, mating faces. A mechanical, sharpened blade, when actuated, passes longitudinally through the central slot following coagulation on each side of the cut.
The Wrublewski et al. U.S. Pat. No. 6,174,309 describes an electrosurgical instrument designed to seal and cut tissue. Embodiments for open and endoscopic procedures are described. In each case, the mating faces of the forceps jaws are such that one has raised electrode surfaces straddling a resiliently mounted cutting blade and the other has a recess for receiving the raised electrode surface therein when the jaws are closed and an intermediate groove in which the resiliently mounted cutting blade may enter. Coagulation takes place when tissue is squeezed between the jaws and a suitable voltage is applied between the raised electrodes on one jaw and on the opposite jaw. Cutting takes place when the voltage is applied between the cutting blade and the jaw having the recesses.
The Rydell et al. U.S. Pat. No. 5,445,638 describes a device somewhat similar to the Fineburg et al. '598 patent described above. It, too, has jaws having planar mating surfaces.
In each of the above-described embodiments, tissue to be coagulated, desiccated is clamped between the jaws of the device and a voltage is applied to the jaws to cause an RF current to flow through the captured tissue to heat and vaporize the moisture in the tissue. Cutting then takes place as a separate step, either by applying a cut voltage to a movable, metal blade member relative to a cooperating jaw or by effecting movement of a sharp blade through the previously desiccated tissue.